Wind turbines are well known and have become an increasingly used application for generating electrical power. Wind turbines are for instance characterized by having an essentially horizontal rotor shaft located in a nacelle framing at the top of a high tower. The essentially horizontal rotor shaft is supporting wind turbine rotor blades. Wind energy is via the rotor blades transferred into kinetic energy by the rotation of the rotor shaft, which in turn is connected to a generator that generates electrical energy. Sometimes also a gearbox is mounted in-between the rotor shaft and the generator. There are also examples of wind turbines arranged with a vertical rotor shaft.
The increased sizes of wind turbines constantly lead to higher requirements of the mechanical components in the wind turbine. One of the most important and demanding mechanical component(s) in a wind turbine is/are the bearing(s) that support the rotor shaft. The supporting bearing(s) for the rotorshaft have to accommodate very high forces, both axial, radial and combinations of axial and radial forces, and also high bending moments and torque.
To this end a number of different bearing types and arrangements are used for supporting the rotor shaft. One example of a bearing arrangement used is to have two tapered roller bearings located remotely from each other to support the rotor shaft. These bearings are designed to be able to accommodate high radial and axial forces (in one direction). By mounting two bearings of this kind remotely (in O- or X-arrangement) onto a rotor shaft it is possible to accommodate radial forces and also axial forces in both directions.